Module 4 : Section 1 - Immunity and Vaccinations Flashcards
Immunity can be…..
- Active
- passive
What is active immunity
When your immune system makes its own antibodies after being stimulated by an antigen.
What are the two types of active and passive immunity
- Natural
- artificial
What is active natural immunity
- When you become immune after catching a disease
- e.g. you have measles or chickenpox so you shouldn’t be able to catch it in later life
What is active artificial immunity
When you become immune after you’ve been give a vaccination containing a harmless dose of antigens
What is passive immunity
The type of immunity you get from being given antibodies made by a different organism, your immune system doesn’t produce any antibodies of its own
What is passive natural immunity
When a baby becomes immune due to the antibodies it receives from its mother, through the placenta and in breast milk (colostrum)
Active immunity…
- requires exposure to antigen
- takes a while for protection to develop
- protection is long term
- memory cells are produced
Passive immunity….
- doesn’t require exposure to antigen
- protection is immediate
- protection is short term
- memory cells aren’t produced
What is passive artificial immunity
- When you become immune after being injected with antibodies from someone else.
- e.g. if if you contract tetanus you can be injected with antibodies against the tetanus toxin, which are collected from blood donations
What happens when an organisms immune system isn’t able to recognise self-antigens
- The immune system treats the self-antigens as foreign antigens and launches an immune response against the organism’s own tissues.
- A disease resulting from this is known as autoimmune diseases
- autoimmune diseases are usually chronic, they can be treated but not cured
Examples of autoimmune diseases
- lupus
- rheumatoid arthritis
What is lupus
- caused by the immune system attacking cells in the connective tissue
- this damages the tissues and causes painful inflammation
- this can affect the skin, joints, and organs such as the heart or lungs
What is rheumatoid arthritis
caused by the immune system attacking cells in the joints, this causes pain and inflammation
How do vaccines work
They contain antigens (maybe free or attached to a attenuated or dead pathogen) that cause your body to produce memory cells against a particular pathogen without the pathogen causing disease - you become immune without getting any symptoms
What happens when most people in a community are vaccinated
The disease becomes extremely rare. Even people who aren’t vaccinated are unlikely to get the disease because there’s no one to catch it from - called herd immunity
What does herd immunity prevent
- epidemics
- mass outbreaks of disease
Why are booster vaccines given
To make sure memory cells are produced later on in the event the pathogen comes back
What is the difference in vaccination and immunisation
- Vaccination is the administration of antigens into the body. This causes immunisation
- Immunisation is the process by which you develop immunity
Give examples of routine vaccines
MMR - protects against measles, mumps and rubella. Usually given to children as an injection when they are about a a year old, it contains attenuated measles mumps and rubella viruses
Meningitis C vaccine - protects against the bacteria that cause meningitis C. It is first given as an injection to babies at 3 months. Boosters are given to 1 year olds and teenagers
Why does the influenza vaccine change every year
- because the antigens on the influenza virus mutate regularly forming new strains if the virus
- memory cells produced from vaccination with one strain of the flu will not recognise other strains with different antigens. They are immunologically distinct
- due to this a new vaccine has to be made
